This week's book giveaways are in the Refactoring and Agile forums. We're giving away four copies each of Re-engineering Legacy Software and Docker in Action and have the authors on-line! See this thread and this one for details.
Assuming you are not using a build tool like Maven*: You manipulate the build path by editing the build path in the project properties. You can select what to export there too. If you want to manipulate the runtime configurations you would edit it in menu "Run", "Runtime configurations...".